A psychrometric model to predict the biological decay of the SARS-CoV-2 virus in aerosols

Abstract

There is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore an analytical study was undertaken using published data to develop a psychrometric model to predict the biological decay rate of the virus in aerosols. This revealed that it is possible to predict with a high degree of accuracy (R 2 = 0.718, p<0.001) the biological decay constant for SARS-CoV-2 using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols was in the region 13-21 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of COVID-19.